Coke removal system



Sept. 19, 1933. w H, BAHLKE COKE REMOVAL SYSTEM Filed March 51, 1931 CUIZZmm H Bahlke 12y K- B W 11g.

Patented Sept. 19, 1933 o STATES PATENT OFFIE (JOKE REMOVAL SYSTEM William H. Bahlke, Hammond, Ind, assignor to Standard Oil Company, (Chicago, Ill., a corporation of Indiana This invention relates to a coke removal system and it pertains more particularly to a means and method of removing solid coke accumulations from reaction chambers or soaking drums used in the distillation or cracking of petroleum hydrocarbons.

Whe'n certain heavy petroleum oils are distilled coke is produced as a residue and when the distillation is at high temperatures coke is formed by cracking (the conversion of oil partly into low boiling point hydrocarbons such as gasoline, and partly into tar or coke). The removal of solid masses of coke from reaction chambers has been a serious problem and the object of my invention is to provide a method and means of solving this problem. A further object is to provide an improved reaction chamber. Other objects will be apparent as a detailed description of the invention proceeds.

In practicing my. invention I prefer to use a reaction chamber having a large removable bottom cover, which may be of the same diameter as the chamber. At spaced intervals around the circumference of the tower and at spaced inter-' vals along the length of the tower I provide apertures which are normally closed by removable plates or plugs. When the reaction chamber becomes filled with a mass of coke, I remove the main cover and I remove the plates or plugsfrom the lower circle of apertures. I then drill a hole into the mass of coke through each of these apertures and I insert charges of an explosive which are suitably wired so that they may be set off simultaneously by closing a switch. By this r means I blast out an increment or section of the coke, and in like manner I blast out the remaining sections thereof.

My invention will be more'c'learly understood from the description of a preferred embodiment, which is illustrated in the accompanying drawing, wherein similar parts are designated by like reference characters in the several figures, and.

introduced by pipe 10 to the lower convectiontubes 11 of pipe still 12. It may then be passed through inner wall tubes 13, floor tubes 14, outer vesselabout ten or fifteen feet in diameter and thirty or forty feet long, and is designed to withstand moderate pressures of about 10-40 pounds per square inch. If an extremely hardcoke is to be removed or if the distillation process is at extremely high pressures, it may be desirable to have the reaction chamber designed to withstand higher pressure.

The-chamber is supported by suitable brackets 20 on a foundation 21. A conduit 22 conducts vapors and reaction products from the top of the chamber to an intermediate point of fractionating tower 23, which. is suitably supported on a foundation 24. Liquid is withdrawn from the base of tower 23 through pipe 25, gases and vapors are removed from the top thereof through pipe 26 and intermediate cuts may be removed through pipes 27. It is to be understood that suitable bubble plates, stripping means, reflux means, entrainment arresters, etc., will be provided in the fractionating tower 23 and that the 8 fluids leaving this tower will be condensed and treated to form gasoline and/or other hydrocarbon products. These features per se form no part of my present invention and they will, therefore,

not be described in detail.

Referring again to the reaction chamber 19, I prefer to have this chamber open at the bottom end and I provide a reenforcing annular flange 28 around the opening of the chamber. If high pressures-and/or large dlameters are used it may be necessary to taper the bottom bf .the chamber inwardly and to cover it with a four foot or six foot manhole cover but I prefer to have the bottom opening as large as the maximum diameter of the chamber. A cover or closure 29 fits the opening and may be held against the end of the chamber by bolts 30, suitably anchored in flange 28 and cooperating with nuts 31. I may, for convenience, provide a hinged mounting for cover 29 and I may use any other suitable means for securing the cover in place.

At about three or four feet from the bottom of the reaction chamber I provide a series of apertures 32 spaced around the circumference of the chamber. The number of these apertures may vary within wide limits, and by way of illustration I have shown them spaced 45 apart. The portion of the-chamber surrounding the apertures is reen'forced by a flange 33 and bolts 34 are 1 imbedded in said flange so that plates 35 may be secured over said apertures by screwing nuts 36 on the bolts. These fastening means are by way of example and it is understood that any equivalent means, such as tapped holes and threaded plugs, may be used.

A similar row of apertures is provided at intervals of three or four feet along the entire length of the tower. These apertures are preferably about an inch in diameter (the drawing is not to scale in this respect).

The operation of my invention is as follows:

The charging stock is heated in pipe still 12 to an elevated temperature, preferably about 800 to 900 F., and is introduced into the reaction chamber 19 (the bottom opening and all of the apertures being closed by the cover plates or plugs). Vapors leave the reaction chamber through pipe 22 and are fractionated in tower 23. The residue in the reaction chamber 19 is maintained at a high temperature by the continued introduction of hot fluids from the pipe still and a process of cracking takes place whereby the hydrocarbons are partly converted into lighter oils, such as gasoline, and partly converted into coke. The coke accumulates on the sides and the bottom of the reaction chamber until the whole container is substantially filled with a solid mass of coke. The flow of oil into the reaction chamber is then interrupted and the contents of the chamber are allowed to cool for fifteen or twenty hours. I prefer to operate a series of reaction chambers so that the process may be continuous, one of said reaction chambers being used while other of said chambers are being cooled, cleaned or repaired.

'When the coke has cooled to a temperature at which workmen might safely remove the bottom cover (about 300 to 400 F.), said cover 29 is removed and closure plates 35 are removed from the lower series of apertures. Holes are drilled into the body of the coke through each of said apertures and an insulated charge of explosive 42 is inserted therein. This explosive may be dynamite and it may be set off by suitable caps or electric firing means which are connected in an electric circuit by means of wires 43. I prefer to introduce these charges at points closer to the circumference of the chamber than to the center, but it should be understood that the holes in the coke may be drilled to any depth and charges may be spaced as desired in any section. By closing the switch 44, I set off the charge of dynamite and blast the section of coke from the open end of the chamber. I then repeat this process at the next row of apertures, etc. until substantially all of the coke is removed.

To hasten the cooling, to improve the quality of the coke and/or to expedite its removal I may introduce steam or water into the reaction chamber through pipe 18. Alternatively, I may employ the fittings shown in Figure 3. Plates 37 may be suitably secured to flanges 33 by screws 36, and integral with plates 37 I may provide short pipes 38 aligned with apertures 32. The ends of these pipes 38 may be closed by plugs 39, and said pipes may be connected through valves 40 to a water or steam main or manifold 41. The valves 40 are as near to pipes 38 as possible. When the chamber is shut down, plugs 39 are removed and by suitable tools or drills the coke is drilled from pipes 38 and holes are drilled part way into the bbdy of coke in the chamber. The plugs 39 are then replaced and valves 40 are. opened to admit steam or cooling water to the chamber. Finally the valves 40 are closed, plugs 39 are removed, the explosive is inserted, and the coke is blasted out as above described.

While I have described a preferred embodiment of my invention it is to be understood that I do not limit myself to the details therein set forth except as defined by the following claims.

I claim:

1. The method of removing solid coke deposits from the open end of a reaction chamber which comprises drilling holes insaid coke at a level spaced from the open end of the reaction chamber, inserting explosive charges in said holes, blasting out an increment of coke by means of said explosive charges, and repeating this process to remove additional increments of coke from said chamber.

2. The method of removing coke from the open end of a reaction chamber which comprises drilling holes in said coke at a spaced distance from said open end, introducing a cooling fluid into said reaction chamber, introducing explosive charges in said holes, and firing said explosive charges to blast an increment of coke from said reaction chamber.

3. In apparatus of the class described a reaction chamber having an open end and having holes at a spaced distance from said open end, means for introducing a cooling fluid into said reaction chamber through said holes, means for introducing explosive charges in said holes, and means for firing said explosive charges to blast an increment of coke from said reaction chamber.

WILLIAM H. BAHLKE. 

